Light source unit and heating treatment device

ABSTRACT

A light source unit of the present invention includes:a board, anda plurality of light source areas formed by a plurality of LED elements mounted on the board, whereineach of the light source areas is provided with a plurality of LED element groups connected in parallel, each of the LED element groups being composed of a plurality of the LED elements connected in series, andat least one of the light source areas is a single-wavelength light source area in which all of the LED elements emit light having substantially a same peak wavelength.

TECHNICAL FIELD

The present invention relates to light source units and heatingtreatment devices, and more particularly relates to a light source unitand a heating treatment device having an LED element as a light source.

BACKGROUND ART

Semiconductor manufacturing process involves various heating treatmentsincluding deposition treatment, oxidation diffusion treatment,modification treatment, and annealing treatment on substrates to betreated, such as semiconductor wafers. The following patent document 1discloses an optical heating device that perform heating treatment onsemiconductor wafers with light emitted from LED elements.

CITATION LIST Patent Document

Patent Document 1: JP-A-2020-009927

SUMMARY OF INVENTION Technical Problem

The equipment of irradiating semiconductor wafers with light in thesemiconductor manufacturing process is expected to be capable ofirradiating the entire surface of the semiconductor wafer (especiallythe main surface) with light having uniform intensity distribution totreat the entire semiconductor wafer uniformly.

The inventors of the present invention have diligently studied a heatingtreatment device that can irradiate the entire substrate to be treated,such as semiconductor wafers, with light more uniformly, and found thefollowing issues.

An LED element has a very small luminance as a single component,compared with other light sources such as a halogen lamp and a dischargelamp. Hence, a heating treatment device that requires high output, suchas heating treatment for semiconductor wafers, needs more than severalthousands of LED elements.

Since the luminance of LED elements varies with the value of the currentflowing through them, a heating treatment device having LED elements asa light source is configured to connect LED elements in series toachieve the value of the current flowing through each of the LEDelements to be equal. However, in the heating treatment device, whichuses more than several thousands of LED elements as described above, ifall of the LED elements are connected in series, a very high voltageneeds to be applied to both ends of the connections for lighting them.

Thus, as a light source installed in the heating treatment device,proposed has been the light source unit that is composed of a pluralityof LED element groups that are connected in parallel, and each of theLED element groups being composed of several to dozens LED elementsconnected in series. The light source unit configured in this way hasthe same current flowing through the LED elements that are included inat least each of the LED element groups.

However, although the voltage applied to the both ends of each of theLED element groups connected in parallel is same, the current flowingthrough each of the LED element groups varies, if the forward voltage(Vf) of each of the LED elements constituting the LED element group isdifferent.

Hence, the light source unit that is composed of a plurality of LEDelement groups that are connected in parallel, and each of the LEDelement groups being composed of LED elements connected in series, hasunacceptably uneven luminance in the treatments that require highuniformity, such as the heating treatment of semiconductor wafers.

In view of the above problem, it is an object of the present inventionto provide a light source unit and a heating treatment device using LEDelements as its light source, the light source unit and the heatingtreatment device for improving the uniformity of light irradiated onto asubstrate to be treated.

Solution to Problem

A light source unit of the present invention includes:

a board having a main surface, and

a plurality of light source areas formed by a plurality of LED elementsmounted on the board, wherein

each of the light source areas is provided with a plurality of LEDelement groups connected in parallel, each of the LED element groupsbeing composed of a plurality of the LED elements connected in series,and

at least one of the light source areas is a single-wavelength lightsource area in which all of the LED elements emit light havingsubstantially a same peak wavelength.

In this specification, the term “LED elements having substantially thesame peak wavelength” refers to LED elements having the differencebetween the longest peak wavelength and the shortest peak wavelength is3% or less with respect to the shortest peak wavelength when the peakwavelength of each of the LED elements is compared.

LED devices emitting light with shorter wavelength, which is higherenergy, have a characteristic of a higher forward voltage. For example,in the visible light wavelength band, LED devices emitting blue lighthave a higher forward voltage than those emitting red light.

Hence, the light source area that are constituted by LED elementsemitting light having substantially the same peak wavelength, has areduced variation in the forward voltage. In other words, theconfiguration described above allows the variation in the forwardvoltage of the LED elements at least in the single-wavelength lightsource area to reduce, compared with the other light source areas, thussuppressing the uneven luminance among each of the LED element groups.

In addition, an LED element emitting light having a shorter peakwavelength tends to form more defects inside the crystal thereof, thusresulting in the shorter operating life of the LED element. In otherwords, the variation in the peak wavelength causes the operating life ofthe LED element to vary. The configuration described above reduces thevariation in the operating life of the LED elements and suppresses theuneven luminance of each of the LED element groups over a long period oftime.

The light source unit described above may include a plurality of smallboards disposed on the board, and each of the light source areas may beformed on a corresponding one of the small boards that are differentwith each other.

The above configuration enables the arrangement of the LED elementgroups to be easily replaced or modified for each small board mounted onthe board. Hence, the above configuration enables the arrangement of theLED element groups, the wavelength band or intensity of the irradiatedlight, or the like, to be suitably adjusted according to thecharacteristics of the substrate to be treated including the type,shape, and size thereof.

In the above light source unit, each of the LED element groups includedin the single-wavelength light source area may have the same number ofthe LED elements connected in series.

The above configuration allows the LED elements that constitute thesingle-wavelength light source area to become their forward voltage morealigned, thus suppressing the uneven luminance of each of the LEDelements.

In the above light source unit, the single-wavelength light source areamay be arranged in a circumferential direction of the board when viewedfrom a direction perpendicular to the main surface of the board.

The term “arranged in a circumferential direction” in this specificationincludes, for example, a case in which a plurality of small fan-shapedboards are combined and arranged to form a circular shape as a whole, ora case in which a light source area is formed to surround one or morelight source areas.

The above configuration improves the uniformity of the light intensitydistribution in the circumferential direction of the main surface of thesubstrate to be treated; in particular, the above configurationsuppresses uneven irradiation to the substrate to be treated having adisk shape such as a semiconductor wafer in the circumferentialdirection, thus achieving light irradiation to the substrate to betreated more uniformly.

In the above light source unit, all of the LED elements mounted on theboard may emit light having substantially the same peak wavelength.

The above configuration allows all of the LED elements mounted on theboard to emit light having substantially the same peak wavelength, thusfurther improving the uniformity of the light irradiated to thesubstrate to be treated.

In the above light source unit, the LED elements included in thesingle-wavelength light source area may emit light having a peakwavelength of 300 nm or more and 1000 nm or less.

In particular, semiconductor wafers made of silicon (Si) (hereinafterreferred to silicon wafers) have a high absorptance and a lowtransmittance for light having a wavelength band from ultraviolet tovisible light; however, the absorptance rapidly decreases and thetransmittance increases as the wavelength becomes longer than 1100 nm.As shown in FIGS. 4A to 4C, which will be referred to in the“DESCRIPTION OF EMBODIMENTS”, approximately 50% of the irradiated lightto the semiconductor wafer having a wavelength of 1100 nm or moretransmits the semiconductor wafer.

In the case of the silicon wafer, when light having a wavelength of 1100nm or more irradiates the surface opposite to the main surface to betreated, a part of the light transmits the silicon wafer and reaches themain surface to be treated. The transmitted light is absorbed on themain surface including the wiring formed thereon, causing variations intemperature distribution and possibly warping or cracking of the siliconwafer. In the case of deposition heating, many deposition types have atendency of exhibiting a large variation in the absorptance at awavelength of 1000 nm or more.

For this reason, the light emitted from the LED elements preferably hasa peak wavelength of 1000 nm or less, in which the absorptance is 50% ormore and the transmittance is 20% or less.

In addition, the absorptance of the silicon wafer decreasesapproximately to 10% at its lowest point for light having a wavelengthof less than 300 nm. Hence, it is preferable that the light emitted fromthe LED elements have a peak wavelength of 300 nm or more in order toensure an absorptance of at least 25% or more.

The above configuration allows the light source unit to perform heatingtreatment of silicon wafers more efficiently. In addition, variation intransmittance and reflectance for light having a wavelength of 300 nm ormore and 1000 nm or less is smaller than those for resistivity variationthat is caused by the amount of ion doping onto the silicon wafer.Hence, the light source unit is capable of heating the wafer uniformlyon the entire surface thereof and at a constant heating rate regardlessof the amount of ion doping.

Moreover, as shown in FIGS. 4A to 4C, the silicon wafer has anabsorptance of 20% or more and a transmittance of nearly 0% for lighthaving a wavelength of 300 nm or more and 1000 nm or less. For thisreason the light in this wavelength range is capable of efficientlyperforming heating treatment only on the outermost surface of thesilicon wafer.

In the above light source unit, the LED elements included in thesingle-wavelength light source area may emit light having a peakwavelength of 300 nm or more and 500 nm or less.

The heating treatment device that is used for, for example, heatingtreatment of substrate to be treated may be provided with a radiationthermometer to measure the surface temperature of the substrate to betreated in order to verify the uniformity of the temperature during thetreatment. The radiation thermometer is a thermometer that measures thesurface temperature of a measurement target by detecting the lightemitted from the measurement target.

The radiation thermometer has a sensitivity wavelength band of mainlynear-infrared to infrared wavelengths (e.g., 0.8 μm to 14 μm), althoughthe sensitivity wavelength band varies slightly depending on themeasurement target and temperature range. Hence, when the light sourceunit emits infrared light and the heating treatment device in which thelight source unit is mounted is provided with the radiation thermometer,the radiation thermometer detects the light emitted from the lightsource unit as stray light.

Therefore, the configuration described above reduces the risk that thelight emitted from the LED elements is detected by the radiationthermometer as stray light even if the sensitivity wavelength band ofthe radiation thermometer is around 0.8 μm.

In the above light source unit, the LED elements included in thesingle-wavelength light source area may emit light having a peakwavelength of 800 nm or more and 900 nm or less.

As shown in FIGS. 4A to 4C, the silicon wafer has a small variation inabsorptance for light having a wavelength range of 800 nm or more and900 nm or less. For this reason, uneven heating is unlikely to occurwhen light having this wavelength range is irradiated to the siliconwafer although the wavelength of the irradiated light differs in eachirradiation area of the silicon wafer.

Therefore, the above configuration is capable of providing the lightsource unit that a variation in the peak wavelength of light emittedfrom the LED elements influences less on the silicon wafer.

A heating treatment device of the present invention is a heatingtreatment device for heating a substrate to be treated, the heatingtreatment device includes:

a chamber for accommodating the substrate to be treated,

a supporter for supporting the substrate to be treated in the chamber,and

the light source unit for irradiating light toward the substrate to betreated.

Advantageous Effects of Invention

The present invention provides a light source unit and a heatingtreatment device using LED elements as its light source, the lightsource and the heating treatment device for improving the uniformity oflight irradiated onto a substrate to be treated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating a configurationof an embodiment of a heating treatment device, viewed in the Ydirection.

FIG. 2 is a schematic view of a light source unit in FIG. 1, viewed fromthe +Z side.

FIG. 3 is a schematic view illustrating a configuration of a smallboard.

FIG. 4A is a graph illustrating the absorptance and transmittancespectrum of a silicon wafer to light.

FIG. 4B is a graph illustrating the absorptance and transmittancespectrum of a silicon wafer to light.

FIG. 4C is a graph illustrating the absorptance and transmittancespectrum of a silicon wafer to light.

FIG. 5 is a view of another embodiment of a light source unit, viewedfrom +Z side.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of a light source unit and a heating treatmentdevice in accordance with the present invention will now be describedwith reference to the drawings. It is noted that each of the followingdrawings related to the light source unit and the heating treatmentdevice is merely schematically illustrated. The dimensional ratios andthe number of parts on the drawings do not necessarily match the actualdimensional ratios and the actual number of parts.

First Embodiment

FIG. 1 is a schematic cross-sectional view illustrating a configurationof an embodiment of a heating treatment device 1, viewed from the Ydirection. As shown in FIG. 1, the heating treatment device 1 of thefirst embodiment is provided with a chamber 10 in which a substrate tobe treated W1 is accommodated, a light source unit 2, and a radiationthermometer 14. The light source unit 2 is provided with a plurality ofLED elements 11 and a board 12 on which the LED elements 11 are mounted.In the first embodiment, the substrate to be treated W1 is considered tobe a silicon wafer; however, the substrate to be treated W1 may includea semiconductor wafer made of materials other than silicon, or a glasssubstrate.

Hereinafter, as shown in FIG. 1, the Z direction is defined as adirection in which the board 12 and the substrate to be treated W1 faceeach other, the X direction as a direction in which a pair of supporters13 face each other, and the Y direction as a direction orthogonal to theX and Z directions. In addition, since the arrangement of the LEDelements that is viewed in the X and Y directions has the samestructure, as shown in FIG. 2 described later, the structure of theheating treatment device 1 is described as a view from the Y direction,unless otherwise necessary.

Moreover, in the case of describing a direction to distinguish apositive direction from a negative direction, a positive or negativesign is added to the direction, such as “+Z direction” or “−Zdirection”. In the case of describing a direction without distinguishinga positive direction from a negative direction, the direction is simplyexpressed as “Z direction”.

As shown in FIG. 1, a chamber 10 is provided with a supporter 13 thatsupports the substrate to be treated W1 inside. The supporter 13supports the substrate to be treated W1 so as to place the main surface(W1 a) of the substrate to be treated W1 on the XY plane.

The supporter 13 can be any configuration as long as the main surface(W1 a) of the substrate to be treated W1 is placed on the XY plane; forexample, the supporter 13 may include a plurality of pin-shapedprotrusions at their points of which the substrate to be treated W1 issupported. Here, the main surface W1 b refers to a surface to whichlight emitted from the LED elements 11 is irradiated.

The chamber 10 is also provided with a monitoring window 10 a that facesthe main surface W1 a of the substrate to be treated W1 supported by thesupporter 13, and a light transmissive window 10 b that faces the mainsurface W1 b of the substrate to be treated W1. The monitoring window 10a is provided to allow the radiation thermometer 14 to measure thetemperature of the main surface W1 a of the substrate to be treated W1.The light transmissive window 10 b is provided to allow the lightemitted from the LED elements 11 in the light source unit 2 andtraveling toward the main surface W1 b of the substrate to be treated W1to enter the chamber 10.

The radiation thermometer 14 is a thermometer that measures the surfacetemperature of a measurement target by detecting the light emitted fromthe measurement target, and has a sensitivity wavelength band ofapproximately 0.8 μm or more and 14 μm or less.

FIG. 2 is a schematic view of a light source unit 2 in FIG. 1, viewedfrom the +Z side. As shown in FIG. 2, the light source unit 2 has aplurality of light source areas 12 a including a plurality of LEDelements 11 arranged on the main surface of the board 12. In the firstembodiment, the light source areas 12 a each are formed on a small board20, which will be described later, and as shown in FIG. 1, the smallboard 20 on which the light source area 12 a is formed is disposed onthe board 12.

The light source unit 2 is disposed on the −Z side of the chamber 10 toallow its light to emit toward the main surface W1 b of the substrate tobe treated W1 supported by the supporter 13 through the lighttransmissive window 10 b of the chamber 10, as shown in FIG. 1.

FIG. 3 is a schematic view illustrating a configuration of the smallboard 20. As shown in FIG. 3, the small board 20 is provided with twoanode electrodes 30 a and two cathode electrodes 30 b, to which electricpower is supplied. A plurality of LED elements 11 are connected betweenthe electrodes (30 a, 30 b) through wiring patterns. Also, Zener diodes30 c are connected between the electrodes (30 a, 30 b) in parallel witha plurality of the LED elements 11. The Zener diodes 30 c are disposedto prevent the LED elements 11 from being damaged by static electricityor surge current.

The LED elements 11 are connected in series to form an LED element group11 s. A plurality of the LED element groups 11 s, each being composed ofthe same number of the LED elements 11, are connected in parallelbetween the electrodes (30 a, 30 b).

The small board 20 is composed of a plurality of single-wavelength lightsource areas in which the LED elements 11 emitting light only havingsubstantially the same peak wavelength are arranged. In the firstembodiment, the small board 20 is composed of the LED elements 11emitting light only having a peak wavelength of 395 nm.

The above configuration allows the LED elements 11 arranged on eachsmall board 20 to have nearly the same forward voltage applied to them,resulting in suppressing uneven luminance of each of the LED elements11, thus further improving the uniformity of light irradiated to thesubstrate to be treated W1.

Hereinafter, the absorption spectrum of a silicon wafer to light isexplained. FIGS. 4A to 4C are graphs illustrating the absorptance andtransmittance spectrum of the silicon wafer to light. FIG. 4A shows theabsorptance and transmittance spectrum in the case in which theresistivity of the silicon wafer is 0.02 Ω·cm, FIG. 4B shows that in thecase in which the resistivity of the silicon wafer is 3 Ω·cm, and FIG.4C shows that in the case in which the resistivity of the silicon waferis 11 Ω·cm.

As shown in FIGS. 4A to 4C, the absorptance and transmittance of thesilicon wafer to light have nearly the same spectrum for all theresistivity values in the wavelength range of 300 nm or more and 1000 nmor less. Hence, the silicon wafer exhibits smaller variation in thetransmittance and reflectance to light having a wavelength of 300 nm ormore and 1000 nm or less, compared with the resistivity variation thatis caused by the amount of ion doping onto the silicon wafer. For thisreason, the light source unit 2 according to the first embodiment iscapable of performing the heating treatment of the main surface W1 b ofthe substrate to be treated W1 uniformly and at a constant heating rateregardless of the amount of the ion doping.

The silicon wafer, as shown in FIGS. 4A to 4C, has an absorptance of 20%or more and a transmittance of nearly 0% for light having a wavelengthof 300 nm or more and 1000 nm or less. For this reason the light in thiswavelength range is capable of efficiently performing heating treatmentonly on the outermost surface of the silicon wafer.

In the light source unit 2 of the first embodiment, the wavelength bandof the light emitted from the LED elements 11 is selected to be 395 nm,this wavelength being in a wavelength range of 300 nm or more and 500 nmor less. As shown in FIG. 4A to 4C, absorptance significantly varieswith respect to wavelength variation in the wavelength range of 300 nmor more and 500 nm or less. However, the light source unit 2 beingcomposed of the LED elements 11 that emit light only havingsubstantially the same peak wavelength suppresses uneven treatment tothe silicon wafer.

Furthermore, the heating treatment device 1 of the first embodiment isconfigured such that the radiation thermometer 14 has a sensitivitywavelength range that is different from the wavelength range of thelight emitted from the LED elements 11. This configuration reduces arisk that the radiation thermometer 14 detects the light emitted fromthe LED elements 11 as stray light.

In the first embodiment, the LED elements 11 are disposed on the smallboard 20 arranged on the board 12 to constitute a plurality of the lightsource areas 12 a; however, the LED elements 11 may be directly disposedon the board 12 to form the light source area 12 a.

Second Embodiment

The following is a description of the configuration of the secondembodiment of the heating treatment device 1, focusing on the pointsthat differ from those of the first embodiment.

The heating treatment device 1 of the second embodiment has the sameconfiguration as that of the first embodiment shown in FIG. 1. The lightsource area 12 a of the light source unit 2 is composed of LED elements11 that emit light only having a peak wavelength of 850 nm.

As shown in FIGS. 4A to 4C, the silicon wafer has a small variation inabsorptance with respect to wavelength variation for light having awavelength range of 800 nm or more and 900 nm or less. Hence the aboveconfiguration is capable of heating the silicon wafer uniformly eventhough the peak wavelength of the light emitted from each of the LEDelements 11 varies.

In the second embodiment, the radiation thermometer 14 is preferablyadopted to have a sensitivity wavelength band of 1 μm or more to preventthe light emitted from the LED element from being detected as straylight. The radiation thermometer 14 may not be provided in aconfiguration in which the heating treatment process is determined bycontrolling time or the like.

Another Embodiment

Hereinafter, another embodiment is described.

FIG. 5 is a view of another embodiment of a light source unit 2, viewedfrom +Z side. In the light source unit 2 of the present embodiment shownin FIG. 5, the areas surrounded by solid lines each indicate the lightsource area 12 a, which is a single-wavelength light source areacomposed of LED elements 11 having substantially the same peakwavelength. And the areas surrounded by dashed lines each indicate thelight source area 12 b, which is not the single-wavelength light sourcearea.

The above configuration enhances the uniformity of light intensitydistribution in the circumferential direction of the main surface W1 bof the substrate to be treated W1. In particular, for the substrate tobe treated W1 having a disk shape, such as semiconductor wafers, unevenirradiation in the circumferential direction is suppressed, leading toachieve more uniform heating treatment.

In the present embodiment, as shown in FIG. 5, the light source areas 12a, which are the single-wavelength areas, are arranged in thecircumferential direction on the main surface of the board 12; however,the light source areas (12 a, 12 b) may not be arranged in thecircumferential direction. In the case that, for example, the heatingtreatment is performed while rotating the substrate to be treated W1 orthe board 12, the light source areas 12 a may be provided only in a partof the board 12 instead of a circle around the center 12 c.

Moreover, in the case that a plurality of the single-wavelength lightsource areas 12 a are formed, light emitted from each of thesingle-wavelength light source areas 12 a may have a different peakwavelength.

<2> In the embodiments described above, the light source areas (12 a, 12b) each are shown as a square and the small board 20 is shown as arectangle; however, they can be a circle or a polygon shape other than aquadrangle. The light source areas (12 a, 12 b) and the small board 20may be arranged to form in a circular shape around the center 12 c ofthe board 12, and each shape of light source areas (12 a, 12 b) andsmall board 20 may be different.

In addition, the LED element groups 11 s each are composed of the samenumber of LED elements; however the number of LED elements includedtherein may be different due to the consideration of the difference involtage drop associated with the respective distance from the anodeelectrode 30 a and cathode electrode 30 b.

<3> The configuration of the heating treatment device 1 described aboveis merely an example, and the present invention is not limited to eachconfiguration shown in the figures.

1. A light source unit comprising: a board having a main surface, and aplurality of light source areas formed by a plurality of LED elementsmounted on the board, wherein each of the light source areas is providedwith a plurality of LED element groups connected in parallel, each ofthe LED element groups being composed of a plurality of the LED elementsconnected in series, and at least one of the light source areas is asingle-wavelength light source area in which all of the LED elementsemit light having substantially a same peak wavelength.
 2. The lightsource unit according to claim 1, further comprising a plurality ofsmall boards disposed on the board, wherein each of the light sourceareas is formed on a corresponding one of the small boards that aredifferent with each other.
 3. The light source unit according to claim1, wherein each of the LED element groups included in thesingle-wavelength light source area has the same number of the LEDelements connected in series.
 4. The light source unit according toclaim 2, wherein each of the LED element groups included in thesingle-wavelength light source area has the same number of the LEDelements connected in series.
 5. The light source unit according toclaim 1, wherein the single-wavelength light source area is arranged ina circumferential direction of the board when viewed from a directionperpendicular to the main surface of the board.
 6. The light source unitaccording to claim 2, wherein the single-wavelength light source area isarranged in a circumferential direction of the board when viewed from adirection perpendicular to the main surface of the board.
 7. The lightsource unit according to claim 1, wherein all of the LED elementsmounted on the board emit light having substantially the same peakwavelength.
 8. The light source unit according to claim 2, wherein allof the LED elements mounted on the board emit light having substantiallythe same peak wavelength.
 9. The light source unit according to claim 1,wherein the LED elements included in the single-wavelength light sourcearea emit light having a peak wavelength of 300 nm or more and 1000 nmor less.
 10. The light source unit according to claim 2, wherein the LEDelements included in the single-wavelength light source area emit lighthaving a peak wavelength of 300 nm or more and 1000 nm or less.
 11. Thelight source unit according to claim 9, wherein the LED elementsincluded in the single-wavelength light source area emit light having apeak wavelength of 300 nm or more and 500 nm or less.
 12. The lightsource unit according to claim 10, wherein the LED elements included inthe single-wavelength light source area emit light having a peakwavelength of 300 nm or more and 500 nm or less.
 13. The light sourceunit according to claim 9, wherein the LED elements included in thesingle-wavelength light source area emit light having a peak wavelengthof 800 nm or more and 900 nm or less.
 14. The light source unitaccording to claim 10, wherein the LED elements included in thesingle-wavelength light source area emit light having a peak wavelengthof 800 nm or more and 900 nm or less.
 15. A heating treatment device forheating a substrate to be treated, the heating treatment devicecomprising: a chamber for accommodating the substrate to be treated, asupporter for supporting the substrate to be treated in the chamber, andthe light source unit according to claim 1, for irradiating light towardthe substrate to be treated.
 16. A heating treatment device for heatinga substrate to be treated, the heating treatment device comprising: achamber for accommodating the substrate to be treated, a supporter forsupporting the substrate to be treated in the chamber, and the lightsource unit according to claim 2, for irradiating light toward thesubstrate to be treated.